JPH03188915A - Solvent recovery device - Google Patents

Abstract

PURPOSE:To improve the condensation efficiency of solvent and to carry the concn. process by an adsorption tower with high efficiency by cooling and condensing the solvent containing gas in such a state that the boiling point is raised by pressurizing solvent contg. gas through a pressurizing means after the solvent contg. gas is concentrated through the adsorption tower. CONSTITUTION:The solvent adsorption body consisting of monolithically formed adsorption material the main component of which is an activated carbon and of the heat supply member brought into contact with the adsorption material is packed in plural adsorption towers 1, 2. The blower means 22, 23 of the solvent containing gas selectively flow the solvent contg. gas to be treated into the adsorption towers 1, 2 to obtain clean gas. The gas discharged from the adsorption tower is pressurized by a pressurizing means 10. The discharged gas pressurized by the pressurizing means 10 is introduced into a condensation cooler 7 to be cooled to condense the solvent in the discharged gas. As a result, the condensation efficiency of solvent is improved, and the concn. process through the adsorption tower is carried out with high efficiency, and the required amount of adsorption material and the equipment cost are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a batch-type solvent recovery device for recovering a solvent from a process gas containing a solvent such as fluorocarbons, and in particular, a method for recovering a solvent without using water vapor during regeneration. It is related to the device.

[Prior Art] Recently, there has been an increased interest in environmental pollution, and regulations have been tightened from the standpoint of environmental conservation, and there is a tendency to prohibit the release of carbon waste into the atmosphere. In particular, air pollution caused by fluorocarbon gases containing chlorine is attracting attention as a serious problem on a global scale, and for this reason, regulations on the emission of fluorocarbon gases are being implemented.

Although these fluorocarbon gas emission regulations call for the complete discontinuation of the use of fluorocarbon gas in the future, during the current period until a replacement product is developed, the fluorocarbon gas that was previously released into the atmosphere will be removed from the system. The next best option is to collect and reuse the waste so that it is not discharged into the environment. For this reason, various fluorocarbon gas recovery devices have been developed.

In conventional batch-type fluorocarbon gas recovery equipment, fluorocarbon-containing gas is selectively and alternately passed through multiple adsorption towers storing adsorbent material, and the fluorocarbons are adsorbed by the adsorbent material in the adsorption towers. clean gas is obtained. After adsorbing fluorocarbons, high-temperature steam is passed through the adsorbent in the adsorption tower, and the adsorbent is heated by this steam.
The adsorbent is regenerated by desorbing fluorocarbons from the adsorbent. In this way, by alternately repeating adsorption and desorption in a plurality of adsorption towers, fluorocarbons are removed from fluorocarbon-containing air and clean air is obtained. If necessary, a cooling gas at room temperature or other low temperature is passed through the adsorption tower after the desorption process to cool the adsorbent and increase its adsorption efficiency before moving on to the adsorption process. There is.

However, such conventional fluorocarbon gas recovery apparatuses have a drawback in that, because water vapor is used to regenerate the adsorbent, it is difficult to avoid the decomposition of fluorocarbons, that is, the generation of acids. That is, when fluorocarbons remain adsorbed on activated carbon for a long time under conditions where they are exposed to water vapor, a portion of the fluorocarbons decomposes, generating hydrochloric acid and hydrofluoric acid. This causes problems such as a decrease in the purity of fluorocarbons in the recovered fluorocarbons and the mixing of acids into waste water and purified gas. Also,
When recovering azeotropic CFCs containing alcohol, the alcohol dissolves in water and most of it is discharged along with the large amount of wastewater.
There are also problems such as the need to take measures against OD and COD.

Therefore, the present inventor proposed a solvent recovery device that does not use water vapor to regenerate the adsorbent (Japanese Patent Application No. 1-144987). This solvent recovery device is designed to heat the adsorbent with a sheet heater, and an example thereof is shown in FIG. That is, adsorbents 40 shown in FIG. 3 are housed in the two adsorption towers 1 and 2.

This adsorbent 40 has a sheet heater 42 interposed between a plurality of activated carbon adsorbents 41. and,
By energizing this seat heater 42, it generates resistance heat, thereby causing the adsorbent 41 in contact with the seat heater 42 to
It is designed to heat up. By stopping the power supply to the seat heater 42, the adsorbent 41 is allowed to cool.

Freon-containing air is supplied to the processing blower 3 via piping 21. The processing blower 3 is connected to a cooler 4 via a pipe 22, and the cooler 4 connects the first and second adsorption towers 1, 1, 2, 3, 3, 4, 3, 3, 3, 4 to 4 using a pipe 23 and pipes 23a, 23b branched from this pipe 23, respectively. It is connected to 2. Freon-containing air is transferred to piping 22, 23.23a by processing blower 3.
, 23b to the first and second adsorption towers 1 and 2. Cooling water is supplied to the cooler 4, which cools the fluorocarbon-containing air sent into the adsorption towers 1 and 2 in advance. In addition, the piping 23a, 2
3b is provided with on-off valves vI and V3, respectively.

The purified air discharged from the first and second adsorption towers 1 and 2 is passed through pipes 24a and 24b and these pipes 24a and 2.
4b is discharged into the atmosphere via the main pipe 24 connected to the main pipe 24. The pipes 24a and 24b each have on-off valves V2. v
4 is interposed.

In addition, the pipe 24 is connected to the pipe 26 a + 27 a and the pipe 2
6b and 27b to one end of each of the first and second adsorption columns 1 and 2, respectively. Piping 2E3
A and 28b are respectively provided with atmospheric release valves Ve and Vs, and each of the pipes 27a and 27b is provided with a carrier air flow rate regulating valve V I Or 'VI 2 . Piping 25a, 25b and piping 28a, 28b are connected to the other ends of the first and second adsorption towers 1, 2, respectively. Piping 25a.

25b joins the pipe 25, and this pipe 25 is connected to the pipe 22. Then, the pipe 25 has a pipe 25
A cooling blower 5 is interposed to suck air from the adsorption towers 1 and 2 through a and 25b, and on-off valves V and V7 are interposed in the pipes 25a and 25b, respectively.

Furthermore, the pipes 28a and 28b merge into a pipe 28, and are connected to the separator 8 via this pipe 28.

A vacuum pump 6 and a cooler 7 are interposed in this pipe 28, and the air inside the adsorption towers 1 and 2 is sucked by the vacuum pump 6 through the pipes 28a, 28b, and 28, and the air inside the adsorption towers 1 and 2 is sucked into the cooler 7. After cooling this suction air, it is sent to the separator 8.

6- Chill cooling water is supplied to the cooler 7, and the fluorocarbon-containing air in the adsorption towers 1 and 2 sucked by the vacuum pump 6 is cooled by this chill cooling water, and the fluorocarbons and moisture in the fluorocarbon-containing air are removed. The condensed fluorocarbon liquid and water are supplied to the separator 8 together with air containing uncondensed fluorocarbons.

In the separator 8, water and fluorocarbon liquid are separated, and the fluorocarbon liquid is collected and recovered in a tank θ.

Moisture is discharged from separator 8. On the other hand, the air containing uncondensed fluorocarbons is returned to the pipe 21 via the pipe 29 and subjected to the adsorption and desorption process again together with the treated air.

Next, the operation of the fluorocarbon recovery device configured as described above will be explained.

First, the adsorbent stored in the first adsorption tower 1 has been regenerated and is in an active state, and the adsorbent stored in the second adsorption tower 2 has been adsorbed and has sufficiently adsorbed fluorocarbons. Suppose we are in a state where Therefore, the first adsorption tower 1 carries out the adsorption process, and the second adsorption tower 2 carries out the desorption process.

In this case, the on-off valve v1. Open v2, open/close valve Vr;, V
Close e and v9. The flow rate regulating valve VIOI VI2 is set so that a predetermined regeneration gas flows therethrough when the pressure inside the adsorption tower is reduced. In addition, on-off valves V3 + V4 + V7
Close rv8, open on-off valve Vll, and flow rate adjustment valve v1□
This flow rate regulating valve V, by setting it to a predetermined opening degree. A predetermined flow rate of regeneration gas is made to flow through the regeneration gas. Further, the processing blower 3 is always driven, and the vacuum pump 6 and the cooling cleaning blower 5 are selectively driven.

Note that at the beginning of this process, the vacuum pump 6 is in an operating state, and the cooling cleaning blower 5 is in an inoperative state.

Then, the fluorocarbon-containing air is sucked by the blower 3 through the piping 21, and is supplied to the cooler 4 through the piping 22, where it is cooled. As a result, the fluorocarbon-containing air is cooled to a low temperature at which the adsorption efficiency of the adsorbent is high, and then sent into the first adsorption tower 1 by the blower 3 via the piping 23.23a. An adsorbent 40 is housed in the adsorption tower 1,
The air containing fluorocarbons passes through the adsorbent 41 of the adsorbent 40, and the fluorocarbons contained therein are adsorbed by the adsorbent 41. The clean air from which Freon has been removed is supplied to the pipe 24a.

24 to the atmosphere.

On the other hand, in the second adsorption tower 2, the inside of the adsorption tower 2 is sucked by the vacuum pump 6 through the pipes 28, 28b, and the purified air flowing through the pipe 24 is adjusted to a predetermined flow rate through the flow rate regulating valve VI2. will be introduced in

In the adsorbent 40 in the adsorption tower 2, electricity is supplied to the sheet heater 42 to cause the sheet heater 42 to generate resistance heat, and the adsorption +A in contact with the sheet heater 42
Heat '41. As a result, the fluorocarbons adsorbed on the adsorbent 41 are desorbed, and the fluorocarbons desorbed from the adsorbent 41 are vacuumed using the purified air introduced into the adsorption tower 2 via the flow rate regulating valve V□2 as a carrier gas. It is sucked by the pump 6 and supplied to the cooler 7. The air discharged from the adsorption tower 2 in which the fluorocarbons are concentrated is cooled by chilled water in the cooler 7, and the fluorocarbons and water in the discharged air are condensed to become a fluorocarbon liquid and water, which are then supplied to the separator 8. The air containing uncondensed fluorocarbons is returned from the separator 8 to the pipe 21 via the pipe 29, and is subjected to an adsorption process by the processing blower 3 together with the fluorocarbon-containing air sent in via the pipe 21. First adsorption tower 1
will be introduced in Therefore, the air containing uncondensed fluorocarbons after condensing fluorocarbons and moisture from the fluorocarbon-concentrated air in the cooler 8 is supplied to the first adsorption tower 1, where the uncondensed fluorocarbons are adsorbed and removed.

In the separator 8, the Freon liquid and water are separated by specific gravity,
The water is discharged and the fluorocarbon liquid is collected in the tank 9.

Next, after sufficiently desorbing fluorocarbons from the adsorbent in the second adsorption tower 2, the second adsorption tower 2 is transferred from the desorption step to the cooling step while the first adsorption tower 1 remains in the adsorption step. to be transferred to That is, valve V11V2. V,,V,,'ve and valve V3. V4 is left as is, opening/closing valve v8 is opened, and opening/closing valve Vll is closed.

By doing this, air is supplied through the pipe 26b into the adsorption tower 2, which had been under reduced pressure until then, and the pressure becomes normal. Next, on-off valve v8 is opened while the other on-off valves remain as they are, and on-off valve v4. Let v7 be closed.

Further, the vacuum pump 6 stops operating, and the cooling cleaning 10-blower 5 starts operating. Then, the purified air flowing through the pipe 24 is sucked by the cooling cleaning blower 5 and introduced into the second adsorption tower 2 via the pipe 24b. This purified air is used as a cooling gas to cool the adsorbent in the second adsorption tower 2, and then passes through the pipes 25b and 25 to the pipe 2.
2 and supplied to the first adsorption tower 1 together with the fluorocarbon-containing air. As a result, the fluorocarbons mixed into the cooling gas when flowing through the second adsorption tower 2 are adsorbed by the adsorbent in the first adsorption tower 1 and removed.

Thereafter, the first adsorption tower 1 is switched to the desorption process, and the second adsorption tower 2 is switched to the adsorption process, and thereafter, such operations are alternately repeated to recover fluorocarbons from the fluorocarbon-containing air.

In this way, the adsorbent can be regenerated without the use of water vapor, which may generate acids.

[Problems to be Solved by the Invention] However, the above-described fluorocarbon recovery device has the following drawbacks.

When the concentration of fluorocarbons in the air is low, the concentration of fluorocarbons in the fluorocarbon concentrated gas sucked by the vacuum pump 6 and sent to the cooler 7 is also low. the result,
The cooling condensation efficiency in the cooler 7 becomes low, and the air returned from the separator 8 to the pipe 21 contains a large amount of uncondensed fluorocarbon. Therefore, in the adsorption towers 1 and 2, in addition to the fluorocarbons in the fluorocarbon-containing air sent into the device via the piping 21, it is also necessary to adsorb and treat the fluorocarbons in the return air that is circulated within the device. Since the amount of fluorocarbon in the return air is relatively large, the required amount of adsorbent to be stored in the adsorption tower increases. Therefore, there is a drawback that the device cost is high.

In addition, since the amount of return air returned from the separator 8 to the adsorption towers 1 and 2 increases, in the adsorption towers 1 and 2, -
The ratio of highly concentrated air being reconcentrated as return air increases, resulting in a wasteful concentration (adsorption and desorption) process.

Then, the adsorbent is used to adsorb and recover the fluorocarbons in this return air, and the proportion of the adsorbent that should be used to treat the fluorocarbon-containing air that should originally be adsorbed and recovered, that is, the fluorocarbon-containing air supplied from the outside system, is reduced. This is extremely inefficient. For example, in Freon 113, the cooler 7 has a temperature of 5°C.
Even if the carrier gas is cooled and condensed and separated, the carrier gas contains a high concentration of uncondensed chlorofluorocarbons, which exceeds the theoretical value of 18% and actually exceeds 20%, and is returned to the inlet of the adsorption towers 1 and 2. Become. The Freon 11 contains an even higher concentration of uncondensed Freon, about 53%, and is returned to the inlets of the adsorption towers 1 and 2. Since the amount of uncondensed fluorocarbons in the return air is large as described above, there is a drawback that the concentration process using the adsorption towers 1 and 2 is not effectively used for concentrating the fluorocarbon-containing air introduced from the outside system.

The present invention has been made in view of such problems, and includes:
The purpose of the present invention is to provide a solvent recovery device that can improve the condensation efficiency of the solvent, make the concentration process using the adsorption tower highly efficient, and reduce the required amount of adsorbed H and the device cost. do.

[Means for Solving the Problems] 13- The solvent recovery device according to the present invention comprises a plurality of solvent adsorbents each containing a monolithic adsorbent whose main component is activated carbon and a heat supply member in contact with the adsorbent. an adsorption tower, a solvent-containing gas flow means for selectively passing a process gas containing a solvent through the plurality of adsorption towers to obtain clean gas, and a pressurizing means for pressurizing the exhaust gas from the adsorption tower. and a condensing cooler that introduces and cools the exhaust gas pressurized by the pressurizing means and condenses the solvent in the exhaust gas.

[Operation] In the present invention, among the plurality of adsorption towers, in the adsorption tower performing the solvent desorption process, the monolithic adsorbent is heated by its heat supply member, and the solvent that has been adsorbed up to that point is heated. Attach and detach.

The solvent concentrated gas containing the solvent desorbed from the adsorbent is pressurized by a pressurizing means and then cooled by a condensing cooler, and the solvent is condensed and separated from the gas. In this case, since the solvent concentrated gas has a pressure higher than normal pressure, its boiling point has increased, and the solvent in the gas is in a state where it is easy to condense. Therefore, even if the solvent-containing gas supplied to the adsorption tower from the outside has a relatively low concentration, and therefore the concentration of the solvent desorbed from the adsorption tower is low, the solvent introduced into the condensing cooler Since the /1'3 condensed gas has a high boiling point, extremely high condensation efficiency can be obtained in the condensing cooler.

Furthermore, since the condensing efficiency in this condensing cooler is high, there is little solvent remaining in the uncondensed gas discharged from the condensing cooler. Therefore, since the adsorption tower is effectively used for concentrating the solvent-containing gall introduced from the outside system, the required amount of adsorbent in the adsorption tower is reduced, and the equipment cost is low.

[Example code] Examples of the present invention will be specifically described below.

FIG. 1 is a block diagram showing a solvent recovery device according to an embodiment of the present invention. In FIG. 1, the same parts as in FIG. 2 are given the same reference numerals, and detailed explanation thereof will be omitted.

In this embodiment, a dry compressor 10 is installed in a pipe 28 that guides the exhaust gas from the adsorption towers 1 and 2 to the condensing cooler 7. This dry compressor 10 is installed at a position between the vacuum pump 6 and the condensing cooler 7 in the piping 28, and the adsorption tower 1, which is sucked by the vacuum pump 6,
The exhaust air of step 2, that is, the freon-concentrated air, is changed from normal pressure to, for example, 7
Pressurize to kg/cm2. Further, a pressure reducing valve V13 is installed in a pipe 29 that returns air containing uncondensed fluorocarbons from the condensing cooler 8 to the inlets of the adsorption towers 1 and 2 of the pipe 21. This pressure reducing valve VI3 reduces the pressure of the high pressure uncondensed fluorocarbon-containing air in the condensing cooler 8, and then supplies the air to the adsorption tower 1.2.

Next, the operation of the solvent recovery device configured as described above will be explained.

First, it is assumed that the first adsorption tower 1 carries out an adsorption process, and the second adsorption tower 2 carries out a desorption process.

Therefore, the adsorbent in the first adsorption tower 1 is in an active state,
The adsorbent in the second adsorption tower 2 adsorbs fluorocarbons in a saturated state or a state close to it. In this case, first, on-off valves V, V2 are opened, and on-off valves V5, V6, and V8 are closed. In addition, on-off valve V31V4. V7. V, close, open/close valve v
, I open.

In addition, the pressure reducing valve VI3 is set to a predetermined opening degree, and the piping 29
The pressure on the condensing cooler 8 side and the pressure on the piping 21 side are adjusted. Then, drive the vacuum bomber and process blower 3.
is always driven.

Then, the fluorocarbon-containing air is supplied to the cooler 4 by the processing blower 3 and cooled, becoming low-temperature air with high adsorption efficiency, and then sent into the first adsorption tower 1. This fluorocarbon-containing air is passed through the adsorbent of the adsorbent housed in the first adsorption tower 1, and after the fluorocarbons are adsorbed and removed, it is discharged into the atmosphere as clean air.

On the other hand, in the second adsorption tower 2, the adsorbent 41 is heated by energizing the sheet heater 42 of the adsorbent 40, and the adsorbent 41 desorbs the fluorocarbons adsorbed in the previous adsorption step. The second adsorption tower 2 is sucked by the vacuum pump 6 and placed under negative pressure, and therefore a small amount of purified air is introduced into the second adsorption tower 2 through the flow rate adjustment valve V12. There is. The fluorocarbons desorbed from the adsorbent in the second adsorption tower 2 are sucked by the vacuum pump 6 and supplied to the dry compressor 10 using the purified air as carrier air. The fluorocarbon-enriched air containing the desorbed fluorocarbons is pressurized to, for example, 7 kg/cn+2 by the dry compressor 10.

Next, this high-pressure freon-concentrated air is supplied to the condensing cooler 7. The fluorocarbons and water contained in this fluorocarbon-concentrated air are cooled and condensed by the condensing cooler 7 to become a fluorocarbon liquid and water, which are then supplied to the separator 8. The fluorocarbon liquid and water are separated by specific gravity in a separator 8, and the fluorocarbon liquid is collected and stored in a solvent tank 9. The air containing uncondensed fluorocarbons discharged from the cooler 7 is transferred from the separator 8 to the pipe 2.
It is supplied to piping 21 via 9. In this case, since the air containing uncondensed fluorocarbons in the condensing cooler 8 is at a high pressure, the pressure is reduced by the pressure reducing valve V□3 and returned to normal pressure, and then the pipe 2
It is returned to 1. This uncondensed Freon-containing air is transferred to the pipe 2
The residual fluorocarbons are adsorbed by the adsorbent in the first adsorption tower 1, and the remaining fluorocarbons are adsorbed by the adsorbent in the first adsorption tower 1, resulting in clean air. and is emitted into the atmosphere.

Next, after the adsorbent in the second adsorption tower 2 has been sufficiently desorbed, the second adsorption tower 2 moves to a step of cooling the adsorbent. That is, after the on-off valve v11 is turned off and the on-off valve V8 is opened to bring the inside of the adsorption tower 2 to normal pressure, the on-off valve V8 is closed again. and,
The vacuum pump 6 and the dry compressor 10 are stopped, and then the on-off valve v4. Open V7 and start driving the cooling blower 5. Further, the power supply to the seat heater 42 of the adsorbent 40 housed in the second adsorption tower 2 is stopped.

As a result, inside the second adsorption tower 2, the pipes 24b, 25
The purified air sucked into the cooling blower 5 through the cooling blower 5 through the cooling blower 5 flows as cooling air, and the adsorbent in the second adsorption tower 2, which has been heated in the previous desorption step, is cooled. While this cooling air flows through the second adsorption tower 2, fluorocarbons in the second adsorption tower 2 are mixed into the cooling air, so the cooling air discharged from the second adsorption tower 2 is passed through the cooler. After being returned to the upstream side of 4, it is supplied to the first adsorption tower 1 which is performing an adsorption step, and the mixed fluorocarbons are adsorbed and removed.

Next, after the adsorbent in the first adsorption tower 1 is saturated or has reached a state close to it, the first adsorption tower 1 undergoes a desorption process and a second adsorption process.
The adsorption tower 2 moves to the adsorption process.

Immediately, on-off valve v1. V2. ■5. Close V6, open/close valve v8
Open. Also, on-off valve v3. Open V4, open/close valve V7
Make 1V11 a leap. Then, the vacuum pump 6 and dry compressor 10 are driven, and the cooling blower 5 is stopped. In addition, the adsorbent 4 housed in the first adsorption tower 1
0 seat heater 42 is energized to heat the adsorbent 41,
Freon is desorbed from the adsorbent 41 in the first adsorption tower 1.

As a result, the first adsorption tower 1 performs the desorption process, and the second adsorption tower 2 performs the adsorption process. After the adsorbent in the first adsorption tower 1 has sufficiently desorbed fluorocarbons, the first adsorption tower 1 moves to a cooling step. That is, the power supply to the seat heater 42 is stopped, and the on-off valve V is closed. is closed and the on-off valve V6 is opened to bring the inside of the adsorption tower 1 to normal pressure, and then the on-off valve V6 is closed again.

Also, the vacuum pump 6 and the dry compressor 10 are stopped, and then the on-off valve V2. ■Open 5 and process blower 5.
Start driving. As a result, the purified air in the pipe 24 is introduced into the first adsorption tower 1, and the adsorbent in the first adsorption tower 1, which had been heated in the previous desorption process, is cooled by the flow of purified air. be done.

Thereafter, the first adsorption tower 1 and the second adsorption tower 2 alternately repeat the adsorption process and the desorption and cooling process. As a result, the fluorocarbon-containing air is continuously adsorbed and clean air is obtained, and the condensed and separated fluorocarbon liquid is collected into the solvent tank 9.

In this embodiment, air containing fluorocarbons introduced into the apparatus from an external system passes through adsorption towers 1 and 2, and the fluorocarbons contained therein are adsorbed and removed by adsorbents in the adsorption towers 1 and 2. Then, by applying electricity to the seat heater and heating the adsorbent, the fluorocarbons adsorbed by the adsorbent are desorbed. In this case, when the fluorocarbon concentration in the fluorocarbon-containing air introduced into the apparatus 21- is low, the concentration of fluorocarbon in the fluorocarbon-enriched air desorbed from the adsorption towers 1 and 2 is also low. However, this medium-concentration freon concentrated air is pressurized by the dry compressor 10 to raise its boiling point, and then is supplied to the condensing cooler 7. Therefore, this pressurized freon concentrated air is condensed with high efficiency in the condensing cooler 7. Therefore, even if the concentration of the fluorocarbon-containing air introduced into the apparatus is low, the condensation efficiency in the condenser cooler 7 is extremely high, and fluorocarbons are recovered with high efficiency.

In addition, since the condensation efficiency in the condensing cooler 7 is high, the return is returned from the condensing cooler 7 to the piping 21 via the separator 8, and is then reintroduced to the adsorption tower 1.2 via the processing blower 3 and cooler 4. The amount of uncondensed CFCs in the air is small. For example, if the fluorocarbon enriched air introduced into the condensing cooler 7 is at normal pressure as in the conventional case, as mentioned above, theoretically! 8%
, in reality more than 20% of uncondensed fluorocarbons remain, but when pressurized to 7 kg/am2 as in this example, 22- the remaining uncondensed fluorocarbons actually decreases to 3%. . Therefore, very little of the fluorocarbons adsorbed and removed by the adsorption towers 1 and 2 are circulated within the system, and are exclusively introduced into the apparatus from outside the system.

For this reason, the adsorption towers 1 and 2 are used exclusively for the adsorption treatment of air containing fluorocarbons, which should originally be adsorbed and removed.Since they can adsorb fluorocarbons extremely effectively, the required amount of adsorbent in the adsorption towers 1 and 2 is A small number is sufficient, and the device cost can be reduced.

Also, if the inlet concentration is as low as 200 ppm, the second
In the conventional solvent recovery device shown in the figure, even if the fluorocarbons only circulate inside the device and do not condense, in this example device, the fluorocarbon-concentrated air discharged from the adsorption towers 1 and 2 is After being pressurized, it is supplied to the condensing cooler 7, so that the freon is sufficiently condensed in the condensing cooler 7. Therefore, in the apparatus of this embodiment, fluorocarbons can be recovered with high efficiency from air containing low concentrations of fluorocarbons.

Note that the present invention is of course applicable not only to the recovery of fluorocarbons but also to the recovery of various other solvents.

[Effects of the Invention] According to the present invention, the solvent-containing gas is concentrated by the adsorption tower and then subjected to cooling and condensation in a state where it is pressurized by the pressurizing means and its boiling point is raised. Even if the concentration of solvent in the gas is low,
The condensation efficiency in the condenser cooler is high and the solvent is recovered with very high efficiency. In addition, because the condensation cooler has a high condensation efficiency, there is very little uncondensed solvent (solvent circulated within the device), and when this is returned to the adsorption tower and subjected to concentration again, the amount of adsorbent required in the adsorption tower is small. suffice, and the equipment cost can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a solvent recovery device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a conventional solvent recovery device, and FIG. 3 is a schematic perspective view showing an adsorbent that does not use steam. be. 1.2; Adsorption tower, 3; Processing blower, 4; Cooler, 5; Cooling blower, 6; Vacuum pump, 7; Condensation cooler, 8; Separator, 9; Solvent tank, 10; Dry compressor, 11
;Pressure reducing valve

Claims (2)

[Claims] (1) A plurality of adsorption towers housing a solvent adsorbent consisting of a monolithic adsorbent whose main component is activated carbon and a heat supply member in contact with the adsorbent, and a treated gas containing a solvent in the plurality of adsorption towers. a solvent-containing gas flow means for selectively passing through to obtain a clean gas, a pressurizing means for pressurizing the exhaust gas from the adsorption tower, and introducing the exhaust gas pressurized by the pressurizing means. and a condensing cooler for cooling and condensing the solvent in the exhaust gas. (2) The solvent according to claim 1, further comprising cooling gas flow means for cooling the adsorbent in the adsorption tower by flowing cooling gas and then returning the exhaust gas to the treated gas. Collection device.